Tilting chair



Sept. 2, 1969 K. G. BLOMBORG TIL'I'ING CHAIR Filed Dec.

United States Patent 3,464,663 TILTING CHAIR Karl Georg Blomborg, Nassjo, Sweden, assignor to Aktiebolaget Blomborgs Melraniska, Nassjo, Sweden, a corporation of Sweden Filed Dec. 1, 1967, Ser. No. 687,180 Claims priority, application Sweden, Feb. 3, 1967, 1,577/ 67 Int. Cl. A47c 1/02 US. Cl. 248373 Claims ABSTRACT OF THE DISCLOSURE A tilting chair supported by a post has two brackets secured to the underside of the chair seat and a tube which is rotatably connected to one of the brackets and houses an axially extending torsion spring rigidly connected to the one bracket. The other end of the spring is connected with a sleeve rotatably mounted in the other bracket. Members are provided for adjusting the relative angular position of the sleeve and the tube.

This invention relates to a chair the seat of which is supported by a post having a foot and in which the chair seat is tiltable relative to the post against the action of a torsion spring which is provided between two brackets secured to the under side of the seat.

The object of the invention is to provide a simple and strong chair construction, such as of the armchair type, wherein the seat is resiliently tiltable and adjustable in dilferent positions of inclination. Another object is to provide a tilting chair construction in which the tilting device is prevented from jamming or squeaking.

Other objects and advantages of the invention will appear from the following description with reference to the accompanying drawing.

FIG. 1 is a top plan view of the chair construction with the chair seat removed, and

FIG. 2 is a partly sectional lateral elevation of the construction.

Two brackets 2 and 4 are adapted to be secured to the underside of a chair seat, not shown, by means of screws, not shown, extending through holes 6 in the brackets. A hollow metallic block 8 is rigidly secured to the bracket 2 substantially midway between the ends thereof. As shown at 12, one end of a tube 10 extends into the block and is welded thereto. At the same end of the tube 10 and coaxially therewith a torsion spring or bar 14 of substantially square cross section is fixedly inserted in a sleeve 16 which is rigidly connected with the tube 10 and has a square hole corresponding to the cross section of the torsion bar 14. By means of a needle bearing 18 provided adjacent the block 8 an external tube 20 is mounted for turning movement on the tube 10. The tubes 20 and 10 extend in coaxial relation to the proximity of the other bracket 4 where they are guided relative each other by a plastic bushing 22 in the manner shown in FIG. 2. The other end of the torsion bar 14 is firmly inserted in a square hole 26 in a thick-walled portion of a sleeve 24. By means of a ball bearing 28 the end of the sleeve 24 near the bracket 4 is mounted for turning movement on a stud 30 rigidly secured to the bracket 4.

The end of the tube 20 near the bracket 4 fits snugly in a thin-walled portion of the sleeve 24. The end of the sleeve 24 removed from the bracket 4 is integrally formed with a projection 32 through which a screw 34 extends laterally of the tube 20. Another projection 36 is secured to the tube 20, such as by welding. In FIG. 2 the major part of the projection 36 is concealed and indicated in 3,464,663 Patented Sept. 2, 1969 "ice dotted lines. The end of the screw 34 is in contact with the adjacent side of the projection 36. By screwing the screw 34 more or less through the projection 32 and thereby increasing or decreasing the contact pressure between the screw and the projection 36 the sleeve 24 and the tube 20 can be adjusted in different angular positions relative each other. Consequently, since the torsion bar 14 is anchored in the thicker end of the sleeve 24, the tension of the bar 14 relative to the tube 20 can be regulated.

As shown in FIG. 1, a lateral projection 38 is secured to the end of the tube 20 near the bracket 2. The free end of the projection 38 is received in a cavity in a member 40 secured to the block 8, and the projection has a limited amount of movement in this cavity. Consequently, the tube 20 has a limited amount of turning movement relative to the block 8 and bracket 2. A projection 42 is secured, such as by welding, to the end of the tube 20 near the bracket 2. Secured to the outer end of the pro jection 42 is a toothed segment 44 the teeth 46 of which are parallel to the axis of the tube 20 and extend laterally of the block 8 as shown in FIG. 1. The extension of the toothed segment 44 at right angles to the plane of the drawing corresponds substantially to the thickness of the block 8 as viewed in FIG. 2. At 48 one end 50' of an arm 50 is pivotally mounted in the block 8. The other end of the arm 50 extends outside the bracket 2 in the form of a handle. In the position of the arm 50 shown in full lines in FIG. 1 the end 50' of the arm is received in the space between two of the teeth 46. In the position of the arm 50 shown in chain-dotted lines the end 50" of the arm is out of engagement with the teeth 46. On the side of the arm 50 removed from the toothed segment 44 as viewed in FIG. 1 the arm has two cam recesses 52 and 54 for cooperation with a locking ball 58 which is forced against the arm by a compression spring 56 shown in dotted lines. As will be seen from FIG. 1, the ball 58 engages the cam recess 52 when the arm 50 is in the position shown in full lines, whereas in the position of the arm 50 shown in chain-dotted lines the ball 58 will be received in the cam recess 54.

About midway between the brackets 2 and 4 the tube 20 is secured to an attachment 60 by means of which the tube 20 is connected to a post 62 which in turn is connected to a foot, not shown. Preferably the post 62 is rotatably and displaceably connected to said foot.

The mode of operation is as follows. The tension of the torsion bar 14 and consequently the resistance to the movement caused by a chair occupant who tilts the seat 'of the chair is adjusted in accordance with the weight of the chair occupant by means of the screw 34 which can be turned such as by a separate wrench or by a lever, not shown, connected to the head of the screw. When the seat is tilted the arm 50 is out of engagement with the teeth 46. In order to adjust a certain position of inclination of the seat, the chair occupant inclines to this position, resulting in that the toothed segment 44, 46 connected to the tube 20 will be moved relative to the block 8 associated with the arm 50. After the desired inclination has been obtained the arm 50 is turned into the position shown in full lines in FIG. 1 in which the end 50 of the arm is engaged between two of the teeth 46. As will appear from the above description the arm 50 can be locked, by means of the spring 56 and the ball 58, in two positions corresponding to the cam recesses 52 and 54 and cannot unintentionally be moved into contact with the teeth 46, for instance if the chair is tilted.

It should be noted that in the embodiment described and illustrated the main function of the tube 10 is to constitute a part on which the tube 20 is mounted. Therefore the tube 10 could end at the place where the needle bearing 18 is located. However, due to the fact that the tube 10 extends as far as the tube 20 and is connected thereto in the manner illustrated it serves as a guide means and results in a more stable construtcion. It will be obvious that the scope of the invention i not limited by the means illustrated for mounting the tube 20 near the block 8.

From the above it will be evident that the chair construction described is simple and stable and practically frictionless during tilting movement.

What I claim is:

1. A chair construction comprising a post having a foot, a seat supported by and tiltable relative to said post, two brackets secured to the underside of the seat, a tube extending between said brackets and secured to the post and having one of its ends connected for turning movement with one of said brackets, and a torsion spring exteding axially through the tube and having one of its ends rigidly secured to said one bracket for counteracting tilting movement of the chair seat, wherein the improvement comprises a sleeve secured to the other end of the torsion spring and mounted for turning movement in the other one of said brackets, said sleeve surrounding the other end of the tube concentrically with a snug fit, and means for adjusting the relative angular position of the sleeve and the tube.

2. A chair construction as claimed in claim 1 wherein said means comprises an axially extending projection of the sleeve, a lateral projection of the tube, and a screw screwed through the first named projection and abutting said lateral projection.

3. A chair construction as claimed in claim 1 and further comprising an inner tube which surrounds the torsion spring and on which the first named tube is mounted for turning movement, one end of the inner tube being rigidly secured to said one bracket, said one end of the torsion spring being anchored at one end of the inner tube, the other end of the inner tube terminating in the proximity of the other end of the first named tube and being connected to the first named tube near the other end thereof.

4. A chair construction as cliamed in claim 3 and comprising a needle bearing for mounting the first named tube on the inner tube.

5. A chair construction as claimed in claim 1 and comprising a ball bearing for mounting said sleeve in the other end of said brackets.

References Cited UNITED STATES PATENTS 163,145 5/1875 Brada 297-328 304,876 9/1884 Wallace et al 297-328 2,130,767 9/1938 Knight 297368 2,760,553 8/1956 Lie 248373 2,845,991 8/1958 Soderberg 248373 2,935,119 5/1960 Lie 297303 3,072,377 1/ 1963 =Blomborg 248373 3,131,904 5/1964 Lie 248373 3,162,420 12/1964 Lie 248373 3,185,429 5/ 1965 Meinhardt 248373 FRANCIS K. ZUGEL, Primary Examiner US. Cl. X.R.

UNITED STATES PATENT OFFXCE a C CELKTIFICAT 0F CORRECTION Patent No. 3: 3 Dated p r- 2, 1969 Inventor(s) KARL GEORG BLOMBORG It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Claim 5, last line, "end" should be one The line should read:

"other one of said bracketsfl' blun'LzJ NHU SEALED DEC 2 969 (SEAL) Afloat:

MM. Fletcher, Jr. i- MBS oner o atents Melting Off 

